SCPS267B March 2017 – February 2020 TCA9803
The RILC parameter describes the maximum allowed pull-down resistance. This parameter comes from the combination of IILC and ICS, and states the maximum resistance that can satisfy the IILC parameter. Note that series resistors on the bus are going to affect this, as seen with other types of buffers (voltage delta across the series resistor. This increases the effective VOL of the external device pulling the bus low).
The calculated resistance of the internal pull-down FET of an external device can be calculated from the VOL and IOL measurements of the external device in question using Equation 1. Take care to consider any series resistors placed in the path from the TCA980x to any external device. Note that RPD is the calculated resistance of the internal pull-down FET, and not a resistor to ground. This is for determining if the external device's output characteristics meet the TCA980x RILC requirement (150 Ω).